Durable alkaline seawater oxidation electrocatalysis over NiFe layered double hydroxide nanosheet arrays enabled by 2,5-dihydroxyterephthalic acid functionalization

Abstract

Seawater electrolysis driven by offshore renewable energy is a feasible approach for large-scale hydrogen production. However, it remains challenging to develop chlorine-resistant and long-lived anodes suitable for large current densities (j). In this work, we fabricate a 2,5-dihydroxyterephthalic acid (DHTA)-modified NiFe layered double hydroxide nanosheet array as a highly efficient and stable electrocatalyst for alkaline seawater oxidation. The catalyst requires only an overpotential of 370 mV to achieve an industrial-level j of 1000 mA cm⁻² and can maintain stable continuous operation for 900 h. Furthermore, the assembled anion exchange membrane water electrolyzer can work stably for up to 800 h at 500 mA cm⁻². Electron paramagnetic resonance and in situ Raman spectroscopy reveal that DHTA functionalization promotes oxygen-vacancy formation and accelerates oxygen evolution reaction kinetics, while its carboxylate groups establish an anionic passivation layer that suppresses chloride-ion adsorption and corrosion, thereby improving both the catalytic activity and operational stability of the catalyst.